William h



Patented May 29, 1888-.

W. H. PARRY.

GROOVE CUTTING: TOOL.

(No Model.)

WITNESS I NITE STAT-ES WVILLIAM H. PARRY, OF NEWV YORK, N. Y.

GROOVE-CUTTING TOOL.

SPECIFICATION forming part of Letters Patent No. 383,589, dated May 29, 1888.

Application [iled February 10, 1888.

To all whom it may concern.-

Be it known that 1, WILLIAM H. PARRY, of the city, county, and State of New York, have invented a new and useful Improvement in GrooveGutting Tools, of which the following is a full, clear, and exact description.

This invention relates to an improvement in groove-cutting tools particularly adapted for use on a routing-machine in connection with a templet, in gaining or dovetailing stairstringers for reception of the treads and risers, and the object of the improvement is to secure greater strength, simplicity, and efficiency than have been heretofore generally attained.

The invention consists of a groovecutting tool constructed substantially as hereinafter fully described, and distinctly claimed.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar letters of reference indicate corresponding parts in all the figures.

Figure 1 represents, in side view, a groovecutting tool formed according to my improvement and in section, a part of a stringer being gained thereby, a bed sustaining the stringer, and a templet for guiding the tool. Fig. 2 is a side View of the said tool taken at right angles to that represented in Fig. 1. Fig. 3 is an inverted plan view of the tool. Fig. 4 is a longitudinal sectional view of the tool on the liner m, Fig. 2. Fig. 5 is a side view,partly in section, of the blank from which the tool is out.

In carrying my invention into effect a short solid round bar of steel is turned off at one end to form a shank, B, adapted to the chuck ofa routingmachine, and in the opposite end a hole, A, is bored lengthwise to a depth equal to about half the length of the unturned portion of the bar, so as to form a blank substan tially as that represented in Fig. 5. The cutters Fand G are then formed,by milling, from the tubular shell surrounding the bore A in such a manner as to projectfrom the under side of the solid cylindrical head 0, which is formed by the unbored and unturned portion of the bar and is adapted to travel while revolving in the guide-slot D of a templet, E, over the -stringer H, at diametrically-opposite points,

and to form approximately cylindrical segments, the concave inner faces, f and g, of which directly face each other, and the par- Sorial No. 163,5 6. (No model.)

allel side edges, f f and gg", of which are sharpened. The convex outer faces, f and 9 are cut ecccntrically from the diagonally-opposite sharpened edgesf and gof the cutters, which project from the head flush with the cylindrical surface of the same, and thus form the cutting-edges to the rear edges, f and g", respectively,which project from points on the heads slightly within the periphery thereof, so as to clear the sides of the groove or gain in cutting. The lower ends of the two cutters are beveled oppositely outward and upward to form the straight though interrupted bottom cutting-edges, f and 9 which are thus in line with the lower ends of the sharpened side edges, ff and g g, respectively,and the diagonally-opposite frontcutting-edges,f and g, are made shorter by an equal amount than the rear edges, f and g, respectively, so that the bottom cuttingedgesf andg are bothinclined lengthwise, but in opposite directions. The real cutting is thus done at thejunct-ions of the side and bottom cutting-edges, ff and g the retraction of the remaining parts of the sharpened edges causing them to clear the sides and bottom of the groove, while serving to give a smooth finish to the same.

The opposite cutters are made to diverge in a downward direction, so that the grooves or gains cut will have a more or less dovetail form to better hold the ends of the treads or other pieces received therein.

Having thus described my invention,whatI claim as new, and desire to secure by Letters Patent, is-

1. A cutting-tool for gaining stair-stringers and kindred purposes, consisting of a'holdingshank, a cylindrical head, and groove-cutters having side cutting-edges and inclined bottom cutting'edges projecting from the outer end of the head, the head and cutters formed on a single piece of steel, substantially as described.

2. A groove-cutting tool consisting of a shank, a head, and opposite downwarddiverging cutters projecting from the outer end of the head, said cutters having diagonally-opposite side cutting-edges and oppositely-inclined bottom cutting-edges, the head and cutters formed of a single piece of steel, substantially as described.

3. As an improved article of manufacture,

a groove-cutting tool formed of a single piece I edges, and the lower ends of the cutters being 10 of steel and consisting of a shank a solid cybeveled upward and outward and inclined lindrical head, and cutters in the shape of oppositely lengthwise to form the bottom outcylindrical segments projecting from diametting-edges, substantially as described. rically-opposite points of the outer end of the head, the outer convex faces of the cutters be- WILLIAM PARRY ing formed reversely eccentric, so as to form \Vitnesses: diagonally opposite cutting side edges and CLARENCE L. BURGER,

other diagonally-opposite retreating side O.SEDGWIOK. 

